Search Publications
SX Phoenicis period-luminosity relations and the blue straggler connection
Cohen, Roger E.; Sarajedini, Ata
This study is aimed at investigating the period-luminosity relation of SX Phoenicis (SX Phe) pulsators in Galactic globular clusters (GGCs) and Local Group dwarf galaxies. We verify isochrone-fitting distances of 46 GGCs by fitting their main sequences to a carefully chosen set of nearby, unevolved subdwarfs. We find that the difference between cl…
The dispersal of pyroclasts from ancient explosive volcanoes on Mars: Implications for the friable layered deposits
Head, James W.; Forget, François; Madeleine, Jean-Baptiste +2 more
A number of voluminous, fine-grained, friable deposits have been mapped on Mars. The modes of origin for these deposits are debated. The feasibility for an origin by volcanic airfall for the friable deposits is tested using a global circulation model to simulate the dispersal of pyroclasts from candidate source volcanoes near each deposit. It is c…
The Optically Unbiased GRB Host (TOUGH) Survey. V. VLT/X-shooter Emission-line Redshifts for Swift GRBs at z ~ 2
Hjorth, Jens; Fynbo, Johan P. U.; Milvang-Jensen, Bo +7 more
We present simultaneous optical and near-infrared (NIR) spectroscopy of 19 Swift γ-ray burst (GRB) host galaxies observed with the VLT/X-shooter with the aim of measuring their redshifts. Galaxies were selected from The Optically Unbiased GRB Host (TOUGH) survey (15 of the 19 galaxies) or because they hosted GRBs without a bright optical afterglow…
The Herschel Exploitation of Local Galaxy Andromeda (HELGA). I. Global far-infrared and sub-mm morphology
Blommaert, J. A. D. L.; Boquien, M.; Roussel, H. +30 more
Context. We have obtained Herschel images at five wavelengths from 100 to 500 µm of a ~5.5 × 2.5 degree area centred on the local galaxy M 31 (Andromeda), our nearest neighbour spiral galaxy, as part of the Herschel guaranteed time project "HELGA". The main goals of HELGA are to study the characteristics of the extended dust emission, focusi…
First spectro-interferometric survey of Be stars. I. Observations and constraints on the disk geometry and kinematics
Hofmann, K. -H.; Meilland, A.; Millour, F. +5 more
Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed infrared-excess and emission lines. The phenomena involved in the disk formation still remain highly debated.
Aims: To progress in the understanding of the physical process or processes responsible for the m…
The VLT-FLAMES Tarantula Survey. VII. A low velocity dispersion for the young massive cluster R136
van Loon, J. Th.; Crowther, P. A.; Bastian, N. +8 more
Detailed studies of resolved young massive star clusters are necessary to determine their dynamical state and evaluate the importance of gas expulsion and early cluster evolution. In an effort to gain insight into the dynamical state of the young massive cluster R136 and obtain the first measurement of its velocity dispersion, we analyse multi-epo…
Spectral Energy Distributions of Type 1 Active Galactic Nuclei in the COSMOS Survey. I. The XMM-COSMOS Sample
Liu, Y.; Aussel, H.; Le Floc'h, E. +39 more
The "Cosmic Evolution Survey" (COSMOS) enables the study of the spectral energy distributions (SEDs) of active galactic nuclei (AGNs) because of the deep coverage and rich sampling of frequencies from X-ray to radio. Here we present an SED catalog of 413 X-ray (XMM-Newton)-selected type 1 (emission line FWHM > 2000 km s-1) AGNs with …
Wide distribution and glacial origin of polar gypsum on Mars
Le Mouélic, S.; Spiga, A.; Le Deit, L. +3 more
The North Polar Cap of Mars is associated with different kinds of superficial sediments, including the Circumpolar Dune Field, interior dune fields and sedimentary veneers scattered over the ice cap. In order to resolve the mineralogical composition and the regional distribution of these sediments, we processed OMEGA and CRISM hyperspectral data w…
Atomic model of the type III secretion system needle
Baker, David; Loquet, Antoine; Sgourakis, Nikolaos G. +8 more
Pathogenic bacteria using a type III secretion system (T3SS) to manipulate host cells cause many different infections including Shigella dysentery, typhoid fever, enterohaemorrhagic colitis and bubonic plague. An essential part of the T3SS is a hollow needle-like protein filament through which effector proteins are injected into eukaryotic host ce…
Energetic particle injections to geostationary orbit: Relationship to flow bursts and magnetospheric state
Nakamura, R.; Sergeev, V. A.; Chernyaev, I. A. +5 more
To address the mechanism and factors controlling the injection of energetic particles to the geostationary orbit (GEO), we analyzed the appearance of injections at the GEO drift shell as observed by LANL spacecraft in the cases where the flow bursts and associated transient dipolarization were detected at the entry to the inner magnetosphere, in t…